Ophthalmic lenses, such as contact lenses, are often packaged in individual packages, typically known as “blister packages.” A blister pack generally consists of a plastic container defining a concave cavity adapted to house a sterile aqueous solution and at least one lens, and a laminate foil used to cover the plastic container and contain the solution and lens therein. Such packaging keeps the lens in a hydrated state before being opened and worn by a user. Often, a lens is contained within a blister package for a significant amount of time while the lens is being shipped and held in storage before use. Therefore, it is important that the aqueous solution be hermetically sealed therein, to ensure that the solution cannot leak out and to prevent contaminants from entering the lens containment area. One method of hermetically sealing the laminate foil to the plastic container utilizes a heating element, or heated seal plate, to create a heat seal between the foil and the area surrounding the plastic container. Heated seal plates typically include a flat face that corresponds to the area of the container surrounding the cavity, such that a heat seal is formed where the seal plate engages and applies pressure and heat against the laminate foil/plastic container.
Unfortunately, under certain conditions a hermetic seal is not formed between the foil cover and plastic shell, which can permit the aqueous solution to leak out of the blister package or contaminants to infiltrate the lens area. Accordingly, needs exist for improvements to ophthalmic lens packaging systems that prevent poor seals from developing between the cover and plastic shell of a blister package. It is to the provision of these needs and others that the invention of present invention is directed.